U.S. patent application number 15/668407 was filed with the patent office on 2019-02-07 for temperature calibration system with separable cooling assembly.
The applicant listed for this patent is Fluke Corporation. Invention is credited to David W. Farley.
Application Number | 20190041274 15/668407 |
Document ID | / |
Family ID | 63144870 |
Filed Date | 2019-02-07 |
United States Patent
Application |
20190041274 |
Kind Code |
A1 |
Farley; David W. |
February 7, 2019 |
TEMPERATURE CALIBRATION SYSTEM WITH SEPARABLE COOLING ASSEMBLY
Abstract
Generally described, embodiments are directed to a temperature
calibration system that includes a closed fluidic system and a
cooling assembly configured to remove heat from the closed fluidic
system. The cooling assembly is configured to move between a
coupled position, in which the cooling assembly is thermally
coupled to (e.g., abutting) a condenser of the closed fluidic
system, and a decoupled position, in which the cooling assembly is
thermally decoupled (e.g., spaced apart) from the condenser of the
closed fluidic system. In at least one embodiment, while in the
decoupled position, components of the cooling assembly may be
protected from damage that may occur at elevated temperatures.
Inventors: |
Farley; David W.; (Orem,
UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fluke Corporation |
Everett |
WA |
US |
|
|
Family ID: |
63144870 |
Appl. No.: |
15/668407 |
Filed: |
August 3, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01K 15/00 20130101;
H02K 9/005 20130101; G01K 15/005 20130101; F25D 19/006 20130101;
F28D 15/0266 20130101; G05D 23/1326 20130101; G05D 23/2401
20130101; G05D 23/1909 20130101; F28D 15/06 20130101 |
International
Class: |
G01K 15/00 20060101
G01K015/00; F25D 19/00 20060101 F25D019/00; F28D 15/02 20060101
F28D015/02; F28D 15/06 20060101 F28D015/06; G05D 23/13 20060101
G05D023/13; H02K 9/00 20060101 H02K009/00 |
Claims
1. A temperature calibration system, comprising: a calibration unit
configured to receive one or more device elements to be calibrated;
a closed fluidic system configured to remove heat from the
calibration unit, the closed fluidic system including a condenser
and an evaporator; and a cooling assembly configured to move
between a coupled position, in which the cooling assembly is
abutting the condenser, and a decoupled position, in which the
cooling assembly is spaced from the condenser by a gap.
2. The temperature calibration system of claim 1, further
comprising compression springs having first ends coupled a fixed
component and second ends coupled to a movable component, the
compression springs being biased to move the cooling assembly from
the coupled position to the decoupled position.
3. The temperature calibration system of claim 1, further
comprising a controller and one or more linear actuators that are
coupled to the controller, the controller being configured to
actuate the linear actuators to cause the cooling assembly to move
from the decoupled position to the coupled position.
4. The temperature calibration system of claim 3, further
comprising a temperature sensor coupled to the controller and
configured to provide a signal indicative of a temperature of the
condenser.
5. The temperature calibration system of claim 4, wherein the
controller is configured to deactivate the linear actuators in
response to receiving a signal from the temperature sensor
indicating a temperature that is above a first threshold
temperature, and to activate the linear actuators in response to
receiving a signal from the temperature sensor indicating a
temperature that is below a second threshold temperature.
6. The temperature calibration system of claim 1, wherein the
cooling assembly includes a thermally conductive cap coupled to a
portion of a cooling device.
7. The temperature calibration system of claim 1, wherein the gap
is less than one inch.
8. A temperature calibration system, comprising: a calibration unit
configured to receive one or more device elements to be calibrated;
a closed fluidic system configured to remove heat from the
calibration unit; a cooling assembly configured to move between a
coupled position, in which the cooling assembly is thermally
coupled to a component of the closed fluidic system, and a
decoupled position, in which the cooling assembly is thermally
decoupled from the component of the closed fluidic system; a
temperature sensor positioned to sense a temperature in the closed
fluidic system; and a controller electrically coupled to the
temperature sensor and configured to receive a first temperature
signal from the temperature sensor, the first temperature signal
being indicative of a first temperature in the closed fluidic
system, the controller configured to compare the first temperature
to a first threshold temperature, wherein in response to the first
temperature being at or above the first threshold temperature, the
controller is configured to cause the cooling assembly to move to
the decoupled position.
9. The temperature calibration system of claim 8, further
comprising one or more linear actuators electrically coupled to the
controller, the controller configured to activate the linear
actuators to cause the cooling assembly to move to the coupled
position.
10. The temperature calibration system of claim 9, wherein the
controller is configured to receive a second temperature signal
from the temperature sensor and compare the second temperature to a
second threshold temperature, the controller being configured to
activate the linear actuators in response to the second temperature
being below the second threshold temperature.
11. The temperature calibration system of claim 10, wherein the
first threshold temperature and the second threshold temperature
are the same.
12. The temperature calibration system of claim 8, wherein the
closed fluidic system is a thermosiphon or a heat pipe, and wherein
the component of the closed fluidic system is a condenser of the
thermosiphon or heat pipe.
13. The temperature calibration system of claim 8, wherein in the
coupled position, the cooling assembly abuts the component of the
closed fluidic system, and in the decoupled position, the cooling
assembly is spaced apart from the component of the closed fluidic
system.
14. The temperature calibration system of claim 8, further
comprising compression springs coupled between the cooling assembly
and the closed fluidic system, wherein, in a natural state, the
compression springs are configured to move the cooling assembly to
the decoupled position.
15. A method, comprising: using a cooling assembly coupled to a
closed fluidic system to remove heat from a component of the closed
fluidic system; sensing a first temperature of the closed fluidic
system; comparing the first temperature to a first threshold
temperature; and in response the first temperature being equal to
or greater than the first threshold temperature, moving the cooling
assembly to a decoupled position in which cooling assembly is
spaced apart from the component of the closed fluidic system.
16. The method of claim 15, comprising: detecting a second
temperature of the closed fluidic system; comparing the second
temperature to a second threshold temperature; and in response to
the second temperature being less than the second threshold
temperature, moving the cooling assembly to a coupled position in
which the cooling assembly is abutting the component of the closed
fluidic system.
17. The method of claim 15, wherein the closed fluidic system is a
thermosiphon or a heat pipe and the component is a condenser.
18. The method of claim 16, wherein moving the cooling assembly to
the coupled position comprises sending an electrical signal to
activate a device that causes the cooling assembly to move to the
coupled position.
19. The method of claim 15, wherein the component is a condenser,
and wherein in the decoupled position, the cooling assembly is
spaced apart from the condenser of the closed fluidic system by
less than one inch.
20. The method of claim 15, wherein the cooling assembly is moved
from the coupled position to the decoupled position by a spring
force.
Description
BACKGROUND
Technical Field
[0001] Embodiments are directed to a temperature calibration system
that utilizes a closed fluidic system, such as a thermosiphon or
heat pipe.
Description of the Related Art
[0002] Many temperature calibration systems utilize a closed
fluidic system for removing heat from a calibration unit.
Typically, the closed fluidic system is a thermosiphon (or a heat
pipe) that transfers fluid in the closed system undergoing phase
changes between a liquid state and a vapor or gaseous state. The
thermosiphon may further be coupled to a cooling assembly to aid in
removing heat from the calibration unit. In general, thermosiphons
and cooling assemblies perform well when operating at lower
temperatures (e.g., below ambient) but are limited in performance
when operating at higher temperatures, such as temperatures above
ambient. At these higher temperatures, pressure in the system can
cause damage to the cooling assembly used to help cool the fluid in
the thermosiphon.
[0003] To prevent damage to the cooling assembly, some existing
temperature calibration systems have limited the upper temperature
limit of the operating ranges of the system. Other temperature
calibration systems utilize an expansion tank that is in fluid
communication with a condenser of the thermosiphon. As fluid in the
thermosiphon rises above a threshold temperature, fluid in a
gaseous state migrates through a port at an upper end of the
condenser to the expansion tank, which is located below the
condenser. When temperatures in the condenser reduce, the gas
migrates back to the condenser and the thermosiphon continues to
operate as usual. Alternative solutions, however, are desired.
BRIEF SUMMARY
[0004] Generally described, embodiments are directed to a
temperature calibration system that includes a closed fluidic
system and a cooling assembly configured to remove heat from the
closed fluidic system. The cooling assembly is configured to move
between a coupled position, in which the cooling assembly is
thermally coupled to (e.g., abutting) a condenser of the closed
fluidic system, and a decoupled position, in which the cooling
assembly is thermally decoupled (e.g., spaced apart) from the
condenser of the closed fluidic system. In at least one embodiment,
while in the decoupled position, components of the cooling assembly
may be protected from damage that may occur at elevated
temperatures.
[0005] One embodiment is directed to a temperature calibration
system comprising a calibration unit and a closed fluidic system.
The calibration unit is configured to receive one or more device
elements to be calibrated. The closed fluidic system includes a
condenser and an evaporator and is configured to remove heat from
the calibration unit. The temperature calibration system further
includes a cooling assembly configured to move between a coupled
position and a decoupled position. In the coupled position, the
cooling assembly abuts the condenser, and in the decoupled
position, the cooling assembly is spaced from the condenser by a
gap.
[0006] Another embodiment is directed to a temperature calibration
system, comprising a calibration unit configured to receive one or
more device elements to be calibrated. The temperature calibration
system further includes a closed fluidic system configured to
remove heat from the calibration unit. The temperature calibration
system further includes a cooling assembly configured to move
between a coupled position, in which the cooling assembly is
thermally coupled to a component of the closed fluidic system, and
a decoupled position, in which the cooling assembly is thermally
decoupled from the component of the closed fluidic system. The
temperature calibration system includes a temperature sensor
positioned to sense a temperature in the closed fluidic system. The
temperature calibration system further includes a controller
electrically coupled to the temperature sensor and configured to
receive a first temperature signal from the temperature sensor. The
first temperature signal is indicative of a first temperature in
the closed fluidic system and the controller is configured to
compare the first temperature to a first threshold temperature. The
controller is configured to cause the cooling assembly to move to
the decoupled position in response to the first temperature being
at or above the first threshold temperature.
[0007] Yet another embodiment is directed to a method comprising
using a cooling assembly coupled to a closed fluidic system to
remove heat from a component of the closed fluidic system and
sensing a first temperature of the closed fluidic system. The
method further includes comparing the first temperature to a first
threshold temperature, and in response the first temperature being
equal to or greater than the first threshold temperature, moving
the cooling assembly to a decoupled position in which cooling
assembly is spaced apart from the component of the closed fluidic
system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0008] In the drawings, identical reference numbers identify
similar elements or acts. The sizes and relative positions of
elements in the drawings are not necessarily drawn to scale. For
example, the shapes of various elements and angles are not
necessarily drawn to scale, and some of these elements may be
arbitrarily enlarged and positioned to improve drawing legibility.
Further, the particular shapes of the elements as drawn, are not
necessarily intended to convey any information regarding the actual
shape of the particular elements, and may have been solely selected
for ease of recognition in the drawings.
[0009] FIG. 1A is a schematic illustration of a cross-sectional
view of a temperature calibration system with a cooling assembly in
a coupled position in accordance with one embodiment.
[0010] FIG. 1B is a schematic illustration of a cross-sectional
view of a temperature calibration system with a cooling assembly in
a coupled position in accordance with one embodiment.
[0011] FIG. 2 is a block diagram illustrating some of the
electrical components of the temperature calibration system of
FIGS. 1A and 1B.
DETAILED DESCRIPTION
[0012] Generally described, embodiments are directed to a
temperature calibration system that includes a closed fluidic
system and a cooling assembly configured to remove heat from the
closed fluidic system. The cooling assembly is configured to move
between a coupled position, in which the cooling assembly is
thermally coupled to (e.g., abutting) a condenser of the closed
fluidic system, and a decoupled position, in which the cooling
assembly is thermally decoupled (e.g., spaced apart) from the
condenser of the closed fluidic system. In at least one embodiment,
while in the decoupled position, components of the cooling assembly
may be protected from damage that may occur at elevated
temperatures.
[0013] FIGS. 1A and 1B show a temperature calibration system 100 in
accordance with one embodiment. The temperature calibration system
100 includes a calibration unit 102 that provides a chamber with a
controlled temperature over a temperature range. The temperature
calibration system 100 includes a heat source 152 (FIG. 2) for
heating the calibration unit 102, and a closed fluidic system, such
as a thermosiphon 104 or heat pipe, for removing heat from the
calibration unit 102.
[0014] In some embodiments, the calibration unit 102 is a dry
calibration unit that includes a thermally conductive material,
such as a metal, and includes one or more openings for receiving
one or more device elements to be calibrated, such as probes or
thermometers. In other embodiments, the calibration unit 102
includes a liquid bath that is heated by the heat source.
[0015] The heat source 152 is any heat source configured to heat
the calibration unit 102. In some embodiments, the heat source may
include Peltier elements, electrodes, cartridge heaters, or any
other suitable heater(s) configured to heat the calibration unit
102.
[0016] Heat is transferred away from the calibration unit 102 by
the thermosiphon 104. The thermosiphon 104 includes an evaporator
106 that is located at the calibration unit 102, a condenser 108
that is separated from the calibration unit 102, and a connecting
tube 110 that places the evaporator 106 in fluid communication with
the condenser 108. In particular, a first end 110a of the
connecting tube 110 is coupled to a port of the evaporator 106 at
the calibration unit 102, and a second end 110b of the connecting
tube 110 is coupled to a port of the condenser 108. The evaporator
106, the condenser 108, and the connecting tube 110 together are a
closed system containing a fluid therein. The evaporator 106 is
configured to allow heat in the calibration unit 102 to transfer to
the fluid, which is in a liquid form, and to cause the heated
liquid to evaporate into gas. The condenser 108 is configured to
cool the fluid in the gas form to cause the fluid to condense into
a liquid form. The fluid in the various forms moves through the
connecting tube 110 between the evaporator 106 and the condenser
108. The fluid may be any fluid or refrigerant, including water,
acetone, methanol, or any other suitable fluid.
[0017] To aid the condenser 108 in cooling the fluid, the
temperature calibration system 100 further includes a cooling
assembly 112. The cooling assembly 112 is configured to be moved
between a thermally coupled position, in which (in the illustrated
embodiment) the cooling assembly 112 abuts the condenser 108 as
shown in FIG. 1A, and a thermally decoupled position, in which the
cooling assembly 112 is spaced from the condenser 108 by a gap as
shown in FIG. 1B. In the thermally coupled position as shown in
FIG. 1A, the cooling assembly 112 abuts a surface of the condenser
108 and acts as a heat sink to remove heat from the condenser 108
to aid the condenser 108 in converting the fluid in gas form
therein into liquid form.
[0018] The cooling assembly 112 includes a thermally conductive cap
116 and a cooling device 114. The cooling device 114 includes a
cooling element 118 that is coupled to the thermally conductive cap
116. The cooling device 114 may be an electrically driven cooling
device that aids in removing heat from the condenser 108. In at
least one embodiment, the cooling device 114 is a Stirling cooler
and the cooling element 118 is a cooling head of the Stirling
cooler. The conductive cap 116 is made a thermally conductive
material, such as a metal, and acts as a heat sink to remove heat
from the condenser 108.
[0019] The cooling assembly 112 may be configured to move between
the coupled and decoupled positions by mechanical components,
electrical components, or a combination thereof. In the illustrated
embodiment, mechanical components, such as compression springs 130,
are used to move the cooling assembly 112 from the coupled position
to the decoupled position, and electrical components, such as
linear actuators 132, are used to move the cooling assembly 112
from the decoupled position to the coupled position. Thus, although
power is utilized to cause the cooling assembly 112 to move from
the decoupled position to the coupled position, power is not
utilized to cause the cooling assembly 112 to move from the coupled
position to the decoupled position. Thus, in the event power is
decoupled from the temperature calibration system 100 and the
cooling assembly 112 is in the coupled position, the cooling
assembly 112 will decouple from the condenser 108 by action of
spring force from the compression springs 130.
[0020] The linear actuators 132, which may be linear solenoids for
example, are coupled between the condenser 108 and the cooling
assembly 112. In the illustrated embodiment, first ends of the
linear actuators 132 are coupled to a movable component, such as a
movable plate 134 coupled to the cooling assembly 112, and second
ends of the linear actuators 132 are coupled to a stationary
component, such as a stationary plate 136 coupled to the condenser
108.
[0021] The compression springs 130 are coupled between the
condenser 108 and the cooling assembly 112. In the illustrated
embodiment, the compression springs 130 have first ends coupled to
the movable plate 134, but may in other embodiments be coupled
directly to the cooling assembly 112. The compression springs 130
have second ends coupled to a stationary component, such as a
stationary part of the linear actuators 132, but in other
embodiments may be coupled to the stationary plate 136 or the
condenser 108. In the illustrated embodiment, the compression
springs 130 surround portions of the linear actuators 132.
[0022] The compression springs 130 and the linear actuators 132 are
located radially outward of the condenser 108. In the illustrated
embodiment, there are three compression springs 130 and linear
actuators 132 (although FIGS. 1A and 1B depict only two of them,
with one in cross-sectional view and the other in side view) that
surround the condenser.
[0023] In a natural uncompressed state, the compression springs 130
are biased to hold the cooling assembly 112 away from the condenser
108 in the decoupled position as shown in FIG. 1B. The linear
actuators 132 are electrically driven and, in response to receiving
an electrical signal, are configured to cause the cooling assembly
112 to abut the condenser 108 in the coupled position. In
particular, the linear actuators 132 compress the compression
springs 130 and thereby cause the cooling assembly 112 to move to
the coupled position as shown in FIG. 1A. Thus, the compression
springs 130 are compressed when in the coupled position.
[0024] When in use, the cooling assembly 112 may abut the condenser
108 in the coupled position during initial operations of the
temperature calibration system 100. In the event the temperature
calibration system 100 is operating at elevated temperatures, such
as temperatures above ambient, the cooling assembly 112 may be
moved to the decoupled position. At elevated temperatures, the
cooling assembly 112, such as a Stirling cooler, has limited heat
sink abilities, thereby limiting the amount the cooling assembly
aids in cooling the vaporized fluid in the condenser 108.
Furthermore, components of the cooling assembly (in the illustrated
embodiment, the Stirling cooler) can be damaged by the elevated
temperatures, such as temperatures at or above 50.degree. C. In
particular, the increased temperatures result in increased
pressure, which can cause fatigue and failure of various components
of the Stirling cooler. Thus, by moving the cooling assembly 112
into the decoupled position, the temperature that the cooling
assembly 112 is exposed to is thereby limited. In that regard, the
cooling assembly 112 may be protected from damage caused by
exposure to higher temperatures in the thermosiphon.
[0025] As mentioned above and shown in FIG. 1B, in the decoupled
position, the cooling assembly is separated from the condenser by a
gap. The gap is any suitable distance that protects components of
the cooling assembly, such as the cooling head of the Stirling
cooler, from the excessive heat of the condenser 108. In one
embodiment for example, the gap is less than one inch and may be
less than a half an inch. While the cooling assembly 112 is
separated from the condenser 108 by the gap, the conductive cap 116
acts as a heatsink for the cooling head 118 and cools the cooling
head.
[0026] After the condenser 108 cools, the cooling assembly 112 may
be moved back into the coupled position as described above.
Although not shown, the condenser 108 may be coupled to an
expansion tank as referred to above to aid in alleviating fluid
pressure and/or cooling the condenser 108 while the cooling
assembly 112 is in the decoupled position.
[0027] FIG. 2 is a block diagram illustrating some of the
electrical components of the temperature calibration system 100 in
accordance with at least one embodiment. The temperature
calibration system 100 includes a controller 150 coupled to a heat
source 152, a cooling assembly 112, a user interface 156, a power
source 158, at least one temperature sensor 160, and linear
actuators 162.
[0028] The user interface 156 may include various inputs such as a
touchscreen display, keyboard, knobs and buttons that allow a user
to interact with the controller 150, and outputs, such as a display
and lights, for communicating with the user. For instance, the user
may input a desired temperature for the calibration unit 102, which
is provided to the controller 150.
[0029] The controller 150, which may be a microprocessor or other
programmed or wired circuitry, includes suitable circuitry and
logic for performing various functions during the operation of the
temperature calibration system 100. The controller 150 is
configured to activate and deactivate the heat source 152, the
cooling assembly 112, and the linear actuators 162. In response to
receiving the desired temperature from the user interface, the
controller 150 may send a signal to the heat source 152 to activate
the heat source 152. A temperature sensor 160 is configured to
provide a temperature signal to the controller 150. In at least one
embodiment, the temperature sensor 160 is located inside of the
thermosiphon 104, such as in the condenser 108, and is configured
to sense the temperature within the thermosiphon 104 or condenser
108.
[0030] The controller 150 is configured to compare the sensed
temperature to one or more thresholds. In response to sensing a
temperature that is above a first threshold temperature, the
controller 150 may activate the cooling assembly 112. In the event
the cooling assembly 112 is not in the coupled position, the
controller may also activate the linear actuators 162 to cause the
cooling assembly 112 to move into the coupled position. In
particular, the controller 150 includes suitable circuitry and
logic to provide a signal to electrically activate the cooling
assembly 112 and the linear actuators 162 which cause the cooling
assembly 112 to move from the decoupled position to the coupled
position and thereby compress the compression springs 130.
[0031] In response to sensing a temperature at or above a second
threshold temperature, the controller 150 may deactivate the linear
actuators 162. In response to deactivating the linear actuators
162, the compression springs 130 move to their natural state, which
thereby causes the cooling assembly 112 to move from the coupled
position of FIG. 1A to the decoupled position of FIG. 1B.
[0032] The second threshold temperature may be a temperature that
is below a temperature that would cause damage to the cooling
assembly 112, which may be a Stirling cooler. In that regard, the
cooling assembly 112, and more particularly the cooling device 114,
can be decoupled from the condenser 108 before the temperature of
the condenser 108 reaches temperatures known to cause damage to
components of the cooling device 114. In at least one embodiment
for example, the second threshold temperature is in the range of
50.degree. C. to 60.degree. C.
[0033] After the condenser 108 has cooled, the controller 150 may
receive a temperature signal and in response to sensing a
temperature below the second threshold, the controller 150 may
activate the linear actuators 162, which causes the cooling
assembly 112 to move into the coupled position which again
compresses the compression springs 130. In some embodiments, the
threshold temperatures used to activate and deactivate the linear
actuators 162, and thus move the cooling assembly 112 between the
coupled and decoupled positions, may be different from each other
and include some hysteresis.
[0034] The power source, which can be a battery or a plug for
coupling to a main power supply, provides power for operating the
temperature calibration system.
[0035] As mentioned above, by using mechanical components for
placing the cooling assembly in the decoupled position and
electrical components to place the cooling assembly in the coupled
position, the cooling assembly can be placed in the decoupled
position in the event the power supplied to the temperature
calibration system is disrupted. Although the springs 130 are
described as compression springs, in other embodiments tension
springs may be used that have a natural state that hold the cooling
assembly in the coupled position and linear actuators are used to
place the cooling assembly in the decoupled position. Furthermore,
the springs may be separate from the linear actuators. In other
embodiments, electrical components may be used to move the cooling
assembly 112 between both the decoupled and coupled positions, or
alternatively, mechanical components may be used to move the
cooling assembly between both the decoupled and coupled
positions.
[0036] Although not shown some surfaces of the abutting components
described above may include a thin layer of insulation materials to
keep the contact surfaces from icing up and also to maximize the
thermal contact efficiency between faces during normal cooling
operation.
[0037] Although a thermosiphon is described in the exemplary
embodiments provided herein, a person of ordinary skill in the art
understands any reference to a thermosiphon in accordance with the
present disclosure may also apply to a heat pipe. Furthermore,
although the actuators are shown and described as being activated
by a controller, the actuators may be actuated by other means, such
as hydraulics or motors.
[0038] The various embodiments described above can be combined to
provide further embodiments. These and other changes can be made to
the embodiments in light of the above detailed description. In
general, in the following claims, the terms used should not be
construed to limit the claims to the specific embodiments disclosed
in the specification and the claims, but should be construed to
include all possible embodiments along with the full scope of
equivalents to which such claims are entitled. Accordingly, the
claims are not limited by the disclosure.
* * * * *